Sigma Power Ceramic 700, 1k and 2k?

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SolidSnake03

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Hey All!

Figured I would start a thread about these since MTC kitchen has them and I’m interested in them. To be honest I don’t know nearly as much about soakers in general outside of king and some of the Gesshin stuff, so wondering if anyone has tried these or has experience with them? I’m very familiar with the Sigma power select stones but those are a totally different beast than these which are soakers.

I’m a fan of sigma power for their select line of stones, really enjoy those overall but haven’t heard or seen too much about these so wondering if anyone’s got some experience with them
 
Unfortunately, MTC does not ship internationally at the moment....otherwise the order button for exactly these stones would have already been pressed... So unfortunately no personal experience.

But have fun with the stones!
 
I have the 1K and 2K. Great SUPER hard stones. Be forewarned, they are very difficult to lap, flatten, and clean. Also it doesn’t matter how long you soak them, water runs straight through the top and out the bottom. I sealed mine on all sides but the top to try to retain more water.
That said, they are very fast cutters that don’t really care what steel you put on them. I have some aogami and hap40 knives and they chew right through them. Despite being fast cutters they produce some very nice edges. I use the 1K for bevel setting straight razors.

If I had to choose one of the two, I would take the 2K. It cuts faster than any 1K I’ve seen, and leaves about a 3K finish.
 
I have the 1K and 2K. Great SUPER hard stones. Be forewarned, they are very difficult to lap, flatten, and clean. Also it doesn’t matter how long you soak them, water runs straight through the top and out the bottom. I sealed mine on all sides but the top to try to retain more water.
That said, they are very fast cutters that don’t really care what steel you put on them. I have some aogami and hap40 knives and they chew right through them. Despite being fast cutters they produce some very nice edges. I use the 1K for bevel setting straight razors.

If I had to choose one of the two, I would take the 2K. It cuts faster than any 1K I’ve seen, and leaves about a 3K finish.
According to the description, the 2k sounds like a stone exactly to my taste!
 
Thanks for that write up on them! Actually answers a lot of my questions. Sounds like they have some similarities to the King Hyper actually in how they eat metal but unlike the King Hyper in that the hyper holds its water quite well. It does best perma soaked like most King stones. Good point about sealing it and that helping with the water management
 
Anybody else here using these have anything to report for how these stones are working out for them. I used my 700 Carbon stone a bit on my TF White #1 Nakiri yesterday and it made quick work or resetting the edge bevel once you get a bit of a slurry going.
 
Thanks for that write up on them! Actually answers a lot of my questions. Sounds like they have some similarities to the King Hyper actually in how they eat metal but unlike the King Hyper in that the hyper holds its water quite well. It does best perma soaked like most King stones. Good point about sealing it and that helping with the water management
I'm guessing the normal king hyper. The soft one (which i do like) is pretty similar to just the king deluxe as far as hardness. If the king deluxe removed metal much faster.
 
Anybody else here using these have anything to report for how these stones are working out for them. I used my 700 Carbon stone a bit on my TF White #1 Nakiri yesterday and it made quick work or resetting the edge bevel once you get a bit of a slurry going.
I mean you could sharpen that knife on on almost anything. Even at very high hardness white steel is going to sharpen easier than basically any cheap soft stainless you could find. You don't need any special abrasives for anything that you find commonly used in kitchen knives and especially not any of the low alloy carbon steels, which are very easy to abrade even at high hardness. That's kinda what makes them nice to use in kitchen knives imo, but you do need SOME abrasion resistance, more than white steel. Super blue is nice, but you gotta remember even at 65+ rc super blue sharpens much easier and goes dull much faster than say vg10 at 60 rc even. Like easily noticeable faster. Splash and go stones will always cut slower than soakers because of the lack of friability and whatnot, generally, but all the stuff they use in kitchen knives up to ZDP can easily be sharpened on any decent splash and go stone without any issues. HAP40 is the one exception because this is a niche tool steel that was repurposed and only used by few. Kurosaki tried the hap40, probably due to influence of cktg crowd, but said no thanks and quit. Its not a good choice for a kitchen knife. Like these companies know what they're doing way more than end users do. They pick the steels they do for a reason, there's a reason almost no one uses hap40 for instance and everyone uses SG2.
 
So what's that reason?
The reason HAP40 isn;t common, I believe, is poor machinability and a tendency to be more warp prone than other choices when used in something like a kitchen knife. I think people look at the one paper benefit of it's improved toughness at high hardness over other steels and they think, wow they would make an excellent alternative. Then when they make it thin enough to capitalize said improved toughness in the way of performance gains, you realize it's warps easier. It can be done, but I don't think the juice is worth the squeeze on either end, for consumers or for knife companies/makers. It's never going to anything more than relatively fringe niche thing. I think folks like cktg like it because it's quite cheap and quite easy to get, unlike say ZDP which is expensive. I have a few knives made of this stuff including the Sukenari. It's a nice knife. Solid workhorse. I'd personally tell folks to opt for the ZDP version every single time tho.

SG2 is stainless, which is huge for mass market. It holds an edge noticeably longer than something like vg10, which for most consumers is a noticeable step up over whatever they've been using, usually German knives, 4116. Despite that it's also tougher than vg10, which means you can make thinner higher performing knives with less risk of edge failure and chipping. Its just a nice well balanced stainless steel which works well in kitchen knives. It's diminishing returns trying to improve performance from here imo. It's just so common that you have an abundance of choices in actually existing production knives to choose from. For that reason alone, it's by far the best bet for most folks.

Japan generally wants steels that are nice to sharpen and take good edges, pretty important is the ability to easily be sharpened on standard waterstones. For the most part everything you see being used fits that bill.
 
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It's always going for what can be used easier or easy enough in absolute terms. But some of us here are going for best possible alternatives, pushing the boundaries. My experience with Hap40 in a professional environment proved to be excellent. Outruns most anything once that blade is properly thinned and sharpened. But since getting there isn't for everyone, it's a moot point, I guess, to talk about how good it could be if.
And I might say the same for aogami super, but talking about Denka. Crazy good edge retention and performance once everything is properly done, to a level that an user of any average AS blade won't understand.
 
It's always going for what can be used easier or easy enough in absolute terms. But some of us here are going for best possible alternatives, pushing the boundaries. My experience with Hap40 in a professional environment proved to be excellent. Outruns most anything once that blade is properly thinned and sharpened. But since getting there isn't for everyone, it's a moot point, I guess, to talk about how good it could be if.
And I might say the same for aogami super, but talking about Denka. Crazy good edge retention and performance once everything is properly done, to a level that an user of any average AS blade won't understand.
I wasn't thrilled by how easily the stuff rusts in the Sukenari version at higher hardness than your standard off the shelf laminated Hap40. The potential is definitely there if you thin it out by hand, I was just saying. It's got noticeably better overall wear resistance to say SG2 but it loses that front end bite or keenness or whatever folks wanna call it just as quickly as the SG2, and nowhere near as long as ZDP which seems to hold it's fine edge through extended use in a way I haven't seen with other stuff used in kitchen. ZDP is also considerably easy to sharpen, seems to much more readily take much higher quality edges, it's also much more stain resistant. Those are all a big deal to me. It takes better edges with less effort and yet it stays sharper for longer. Being far less likely to rust out is also a big deal for a brain damaged monkey like myself. Not a great feeling when your ADD results in you rusting out a $400 sukenari.

Other aspects of it though like the fact that it's cheap and easy to procure in laminated sheets makes it an interesting choice if you were for instance creating an in house line of workhorses for commercial users. I understand why they use such a soft lamination on those too cuz the core itself is very much not nice to machine and work with.
 
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I like ZDP-189 as it can keep an usable edge for a really long time, but you will find it's not really a loved alloy in general and most get poor experiences while sharpening and using it.
*We might be well OT in this thread.
I'm one old user of Sigma stones. I have a 2k around somewhere, used it for stainless mainly before slowly moving entirely to diamond these days.
 
I like ZDP-189 as it can keep an usable edge for a really long time, but you will find it's not really a loved alloy in general and most get poor experiences while sharpening and using it.
*We might be well OT in this thread.
I'm one old user of Sigma stones. I have a 2k around somewhere, used it for stainless mainly before slowly moving entirely to diamond these days.
I believe the knife community is extremely prone to myth, bs, irrational and superstitious "thinking" and such, critical thinking is in short supply. Just keeping it real. I haven't seen much of that on this forum, but in general it's very true about "knife bros." Lots of myths and other silliness around knives such topics. I don't think anyone that's actually used it has had bad experience sharpening or using it. Another thing, sharpening is highly over complicated by a lot of people who make it into a challenge that it's just not. It's not some insanely hard skill to learn. On a basic level it's one of the easiest skills you will ever learn in your life. There are endless nuances and subtleties that come later. Again, I think the preponderance of little adolescent aged boys in the knife community pollutes perceptions based on what people hear being talked about on forums and whatnot. Just curious do you own any zdp? Every single person I've spoken to that actually owns and has used the stuff is almost as enthralled as I am/was. If you want input from knife community folks who are worth listening to, ask someone like I forget his name but the Kase knives fella, nice guy, quite knowledgeable. Michael Cristy has a decent video talking about his experience with it on an edc context, I've very rarely heard him make factually unsound statements.

It is ot. These sigma stones aren't needed for zdp. Folks who have actually put that stuff to stone know that it's not especially hard to sharpen at all with regular ol sng stuff. I'm pretty sure it was designed that way intentionally. I haven't tried one on hap40, but I bet it would be a decent choice particularly the 240 and 400 but I'd be very curious to see how the 1k and 2k does, that's what really counts. I wasn't happy with the way any shapton or naniwa reacted at the 1k grit to hap40. The way this side thread started was pointing out that there isn't any particular reason to be using such a stone on something like white steel or even blue steel as even super blue which is the hardest, highest carbon and highest alloy version of those steels at 65+ rc is way easier to grind/machine than even vg10 at 60. These carbon steels basically melt on even slow stones. Seems silly to use a stone made for tenacious steels on stuff like that.
 
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Yes, I think that I had ZDP-189 from pretty much all manufacturers with kitchen and pocket knives. And same goes for most Hap40 blades, too.
This is a delicate subject. I agree with you that sharpening is a (simple) motor skill. One day it hit me that this was actually the simple part. It's exactly how I start teaching. Sounds like nothing really fancy. Until you realise that most people today can't even handle longer periods of practice for results. I have first hand experience with this. And pushing for results without having the skill set and without understanding the physics (that can't be changed or ignored without some shortcomings), makes for a bad experience that's very difficult to change.
 
Yes, I think that I had ZDP-189 from pretty much all manufacturers with kitchen and pocket knives. And same goes for most Hap40 blades, too.
This is a delicate subject. I agree with you that sharpening is a (simple) motor skill. One day it hit me that this was actually the simple part. It's exactly how I start teaching. Sounds like nothing really fancy. Until you realise that most people today can't even handle longer periods of practice for results. I have first hand experience with this. And pushing for results without having the skill set and without understanding the physics (that can't be changed or ignored without some shortcomings), makes for a bad experience that's very difficult to change.
I think there are two camps. One is the scared to ruin my precious knife camp, the other is the "I don't actually care as much as I say I do." Just do it. Start with white steel on a hard stone to build confidence if you have to. Anyone that does a legit lets say 1or 2 hours will come with basic skills they can build on going forward. Once you log lets say a solid 20 hours of stone time with different stones, different steels, knives, you will fairly well know what you're doing. I don't care how untalented you think you are, it's not that hard but the time is a must.
 
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I believe the knife community is extremely prone to myth, bs, irrational and superstitious "thinking" and such, critical thinking is in short supply. Just keeping it real. I haven't seen much of that on this forum, but in general it's very true about "knife bros." Lots of myths and other silliness around knives such topics. I don't think anyone that's actually used it has had bad experience sharpening or using it. Another thing, sharpening is highly over complicated by a lot of people who make it into a challenge that it's just not. It's not some insanely hard skill to learn. On a basic level it's one of the easiest skills you will ever learn in your life. There are endless nuances and subtleties that come later. Again, I think the preponderance of little adolescent aged boys in the knife community pollutes perceptions based on what people hear being talked about on forums and whatnot. Just curious do you own any zdp? Every single person I've spoken to that actually owns and has used the stuff is almost as enthralled as I am/was. If you want input from knife community folks who are worth listening to, ask someone like I forget his name but the Kase knives fella, nice guy, quite knowledgeable. Michael Cristy has a decent video talking about his experience with it on an edc context, I've very rarely heard him make factually unsound statements.

It is ot. These sigma stones aren't needed for zdp. Folks who have actually put that stuff to stone know that it's not especially hard to sharpen at all with regular ol sng stuff. I'm pretty sure it was designed that way intentionally. I haven't tried one on hap40, but I bet it would be a decent choice particularly the 240 and 400 but I'd be very curious to see how the 1k and 2k does, that's what really counts. I wasn't happy with the way any shapton or naniwa reacted at the 1k grit to hap40. The way this side thread started was pointing out that there isn't any particular reason to be using such a stone on something like white steel or even blue steel as even super blue which is the hardest, highest carbon and highest alloy version of those steels at 65+ rc is way easier to grind/machine than even vg10 at 60. These carbon steels basically melt on even slow stones. Seems silly to use a stone made for tenacious steels on stuff like that.
Sounds like these really aren't a great choice for anything then. If they're not needed for higher wear resistance normal steels, and they start becoming necessary for things like hap40. Hap40 is right around the area where if you are sharpening. You should probably pick up some kind of diamond or cbn abrasive.

I do think these could make sense though. I think these sigma select 2 ceramics would be perfect for thinning something like a honyaki, or anything thats a lot of very hard steel.
 
And yet we are at a place when reading for more than 20 seconds it's considered a challenge.
So how does sigma do on your hap40? Particularly in the 1k/2k grit range. Or are you just over that and using what I'm assuming are bonded diamond stones on it now. I agree that would be ideal, but those bonded diamond stones are rare and expensive, only recently become commercialized in any kind of consumer market way at all. The first time I did mine I started off with a 2k shapton pro, wasnt happy or paitent so I switched to a 1k shapton glass, same result so I grabbed a well broken in dmt 325 and went to the 400 chosera to clean it up. I can't remember what I did after that, I might have tried to go back to 1k stone for a minute just to clean it up, but I remember deburing on another stone I think it was 5k shapton pro, which actually did alright bringing up a polish, and then it was all diamond powder on wood from there, I used 1.5-3 micron diamond powder but I remember wishing I had something more aggressive. The diamond is what worked the best, by far. Realistically you could go straight from either 325 plate or the 400 stone to the diamond powder on wood and get similar results. I wouldn't even bother some .5 micron diamond powder either, I'd go with something closer to 5 microns to start.

Sounds like these really aren't a great choice for anything then. If they're not needed for higher wear resistance normal steels, and they start becoming necessary for things like hap40. Hap40 is right around the area where if you are sharpening. You should probably pick up some kind of diamond or cbn abrasive.

I do think these could make sense though. I think these sigma select 2 ceramics would be perfect for thinning something like a honyaki, or anything thats a lot of very hard steel.
Well, maybe you mean bonded diamond but those are rare and expensive and most people really have no legit need to justify such a thing, especially not for kitchen knives unless of course you have something like custom k390 kitchen knives or something. Diamond plates do work, and well broken in one can do alright but the quality of the edge isn't going to be up the level of what you can do with the 240 much less the 400. That's the benefit. Obviously if you have something like the naniwa diamond stones, which cost 3x as much as some sigmas, then you wouldn't need a stone like this or say silicon carbide. It's all a matter of preference at that point.

So basically it's like this, if the choice is diamond plate vs sigma, I'm going for the sigma every time, unless I'm a rush and I don't care ofc. I believe most sharpeners would agree with me there. However if you have access to something like a bonded diamond stone, chances are that's what's gonna get used.

If you're gonna spend the money on a bonded diamond stone, I wouldn't get one in a course grit. You can use course regular stones as basically sharpeners for steels like that, basically dropping grits to get it done, the benefit would be once you're getting into sharpening grits and beyond. Its not as much of an issue at the lower grits but at the sharpening grits something that can cleanly cut the carbides is ideal. At the high end for finishing the diamond powder is fine. So the most bang for your buck if you go with the bonded diamond will be in that 800-3k range imho.
 
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I believe the knife community is extremely prone to myth, bs, irrational and superstitious "thinking" and such, critical thinking is in short supply. Just keeping it real. I haven't seen much of that on this forum, but in general it's very true about "knife bros." Lots of myths and other silliness around knives such topics. I don't think anyone that's actually used it has had bad experience sharpening or using it. Another thing, sharpening is highly over complicated by a lot of people who make it into a challenge that it's just not. It's not some insanely hard skill to learn. On a basic level it's one of the easiest skills you will ever learn in your life. There are endless nuances and subtleties that come later. Again, I think the preponderance of little adolescent aged boys in the knife community pollutes perceptions based on what people hear being talked about on forums and whatnot. Just curious do you own any zdp? Every single person I've spoken to that actually owns and has used the stuff is almost as enthralled as I am/was. If you want input from knife community folks who are worth listening to, ask someone like I forget his name but the Kase knives fella, nice guy, quite knowledgeable. Michael Cristy has a decent video talking about his experience with it on an edc context, I've very rarely heard him make factually unsound statements.

It is ot. These sigma stones aren't needed for zdp. Folks who have actually put that stuff to stone know that it's not especially hard to sharpen at all with regular ol sng stuff. I'm pretty sure it was designed that way intentionally. I haven't tried one on hap40, but I bet it would be a decent choice particularly the 240 and 400 but I'd be very curious to see how the 1k and 2k does, that's what really counts. I wasn't happy with the way any shapton or naniwa reacted at the 1k grit to hap40. The way this side thread started was pointing out that there isn't any particular reason to be using such a stone on something like white steel or even blue steel as even super blue which is the hardest, highest carbon and highest alloy version of those steels at 65+ rc is way easier to grind/machine than even vg10 at 60. These carbon steels basically melt on even slow stones. Seems silly to use a stone made for tenacious steels on stuff like that.

I never said these stones were needed for White #1 but simply said I had occasion to use it on this and nothing unsurprising there. I got a few of these for $36 a pop so it makes no difference at that price and the wear characterstics are pretty impressive to where I don't see a reason not to use this on 'easy' steels. Sure, I could use a KING on this without problem but it was a breeze to use and flatten. King would be messy and take more work likely in grinding and flattening.
 
I never said these stones were needed for White #1 but simply said I had occasion to use it on this and nothing unsurprising there. I got a few of these for $36 a pop so it makes no difference at that price and the wear characterstics are pretty impressive to where I don't see a reason not to use this on 'easy' steels. Sure, I could use a KING on this without problem but it was a breeze to use and flatten. King would be messy and take more work likely in grinding and flattening.
That's sweet. These things aren't always easy to get in every market and usually cost quite a bit more. I'm assuming you got em from MTC on clearance.
 
You can buy DMD or Venev bonded diamond for pretty cheap now, and I would recommend everyone just get one to try outs the edge they put on a knife is lovely.
 
The reason HAP40 isn;t common, I believe, is poor machinability and a tendency to be more warp prone than other choices when used in something like a kitchen knife. I think people look at the one paper benefit of it's improved toughness at high hardness over other steels and they think, wow they would make an excellent alternative. Then when they make it thin enough to capitalize said improved toughness in the way of performance gains, you realize it's warps easier. It can be done, but I don't think the juice is worth the squeeze on either end, for consumers or for knife companies/makers. It's never going to anything more than relatively fringe niche thing. I think folks like cktg like it because it's quite cheap and quite easy to get, unlike say ZDP which is expensive. I have a few knives made of this stuff including the Sukenari. It's a nice knife. Solid workhorse. I'd personally tell folks to opt for the ZDP version every single time tho.

SG2 is stainless, which is huge for mass market. It holds an edge noticeably longer than something like vg10, which for most consumers is a noticeable step up over whatever they've been using, usually German knives, 4116. Despite that it's also tougher than vg10, which means you can make thinner higher performing knives with less risk of edge failure and chipping. Its just a nice well balanced stainless steel which works well in kitchen knives. It's diminishing returns trying to improve performance from here imo. It's just so common that you have an abundance of choices in actually existing production knives to choose from. For that reason alone, it's by far the best bet for most folks.

Japan generally wants steels that are nice to sharpen and take good edges, pretty important is the ability to easily be sharpened on standard waterstones. For the most part everything you see being used fits that bill.
If I remember correctly @Troopah_Knives made some Rex45 stuff before, it shouldn’t be harder to machine than other high MC stuff, with plate quench wrapping is not as bad.
 
You can buy DMD or Venev bonded diamond for pretty cheap now, and I would recommend everyone just get one to try outs the edge they put on a knife is lovely.

Interesting. Where do you get the Venev? The way I understand it is that is a Russian export which wont be available in the US beyond whatever is already in country before trade embargo took effect. Also what's the Chinese one like? How do the stated grit ratings compare to well known Japanese products for instance? How do they cut, feel, wear, etc compared to equivalents?

I tried to get the Venev from gritomatic to try it out but never found any full size, been sold out for a minute. Never heard of the Chinese product but it looks interesting. I'm always down to see what they have to offer, before we end up embargoing their **** too. I'm a fan of their pocket knives and stuff like that, which they're really good at making, and you can import directly for like anywhere from 50%-90% less than an identical equivalent marketed in North America would cost, anyway, but I've never really tried any Chinese stones other than the Amazon Basics one.
 
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Hapstone, they ship directly from Ukraine. Embargo doesn't affect civilian goods, especially niche products like this, it might affect the factory's ability to acquire raw material, but most raw abrasive are manufactured in Henan, China anyway. I just bought a knife from Andrei, tho his having trouble acquiring materials. Venev use FEPA-F/GOST 9206-80 standards, Gritomatic literally have a comparison chart on their page. They cut on par with most waterstone, not as fast as people think but not slow either, there's no feel, kind like hard leather, basically don't wear at all. DMD resin diamond is available on AliExpress, tho sometimes they have QC issues like uneven surafce, but they cut. Even premium Diamond like JKI or Nanonhone are really cost effective, they might be 3 times more expensive than SG stone, they last a lot longer, Jon only flat his stone once per year in a professional sharpening service, so cost is really not the issue on the long term.
https://hapstone.pro/diamond-and-cbn/PHE-OCB100-800.1200https://cdn.shopify.com/s/files/1/0984/5900/files/glgc.webp?v=4355774606081897861
 
It's always going for what can be used easier or easy enough in absolute terms. But some of us here are going for best possible alternatives, pushing the boundaries. My experience with Hap40 in a professional environment proved to be excellent. Outruns most anything once that blade is properly thinned and sharpened. But since getting there isn't for everyone, it's a moot point, I guess, to talk about how good it could be if.
And I might say the same for aogami super, but talking about Denka. Crazy good edge retention and performance once everything is properly done, to a level that an user of any average AS blade won't understand.

I love my hap40 Nakiri. It is a cheaper laminate - but that is exactly why I like it. The blade was under $100 and I made a handle for it.


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If I remember correctly @Troopah_Knives made some Rex45 stuff before, it shouldn’t be harder to machine than other high MC stuff, with plate quench wrapping is not as bad.

I'm not exactly sure why HAP40 has such a reputation for being a ***** to work with. I don't have any experince with HAP50 but I've heard from a source that does that even that stuff is nicer to work than 40 with despite having just as much abrasion resistance and hardness and whatnot. Rex45 is supposed to be basically Crucibles equivalent to the Hitachi one, I don't have any experience with that either. My main gripes about it are mostly related to the machinabilty, the sharpening is clearly more involved than just about anything else you're gonna find on a production kitchen knife, the resulting edges take more finesse to get them nice n crispy, but they lose that front end crispness about the same as SG2, maybe even slightly worse imo. The overall "edge retention" is higher but I never let my own stuff get that dull in the first place. Lack of widespread adoption is an issue too, not many knives to pick if you wanna try it. I like stuff that you can prep a week of food and still have its "fine edge." I've only seen that from zdp.

I love my hap40 Nakiri. It is a cheaper laminate - but that is exactly why I like it. The blade was under $100 and I made a handle for it.


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Nice. I use my Sukenari hap40 210 ktip for the same use basically, a veggie mobile. Is that a 600 chosera?
 
I'm not exactly sure why HAP40 has such a reputation for being a ***** to work with. I don't have any experince with HAP50 but I've heard from a source that does that even that stuff is nicer to work than 40 with despite having just as much abrasion resistance and hardness and whatnot. Rex45 is supposed to be basically Crucibles equivalent to the Hitachi one, I don't have any experience with that either. My main gripes about it are mostly related to the machinabilty, the sharpening is clearly more involved than just about anything else you're gonna find on a production kitchen knife, the resulting edges take more finesse to get them nice n crispy, but they lose that front end crispness about the same as SG2, maybe even slightly worse imo. The overall "edge retention" is higher but I never let my own stuff get that dull in the first place. Lack of widespread adoption is an issue too, not many knives to pick if you wanna try it. I like stuff that you can prep a week of food and still have its "fine edge." I've only seen that from zdp.
That's why I recommend diamond stones for that, I have high VC or WC steel, the egde they got from conventional stone will collapse quicker and loose the "sharpness", but the diamond edge last long and have impressive amount of bite. If anything the carbide type in Hap40 should be finer than ZDP189. personally I had ApexUltra keep a screaming edge for weeks, there's also testimony and video show ApexUltra keep a paper towel slicing edge after 4 weeks in professional kitchen.
 
That's why I recommend diamond stones for that, I have high VC or WC steel, the egde they got from conventional stone will collapse quicker and loose the "sharpness", but the diamond edge last long and have impressive amount of bite. If anything the carbide type in Hap40 should be finer than ZDP189. personally I had ApexUltra keep a screaming edge for weeks, there's also testimony and video show ApexUltra keep a paper towel slicing edge after 4 weeks in professional kitchen.
ZDP is intended for kitchen knives and Hitachi deliberately set out to get those carbides very small. All that stuff is why it's expensive, just as a material. The stuff is special because despite all that, it's very high edge retention, it's sharpens incredibly easily relative to anything else which can perform anywhere close to it. That's what makes a good kitchen knife steel and a good "user steel." I feels a lot like super blue that just stays sharp several times longer, in my opinion. It's easily able to get extremely keen and it stays that way longer than you'd expect. HAP40 has tons of potential too, but you gotta get it thin enough to even make use of it's toughness advantage if you're seeking ultimate performance. One aspect of that is the workflow, needing upgraded abrasives unlike other kitchen knife materials, and like I mentioned needing thin grinds to take advantage of the stuff being as hard and tough as it is. I don't expect to see many production kitchen knives in either steel going forward for different reasons in each case.

I do use diamonds for HAP40. Regardless of what's used to shape the edge and whatnot, be it sintered alumina like these stones, or silicon carbide, or a diamond plate, or even just a course stone like a 320 SP or 400/600 chosera, I always finish it on diamonds.

I'm gonna guess those experiences with AU are down to the combo of being a very fine grained lower alloy steel at very high hardness with good toughness, and then taking advantage of that in the form of a thinness. The steel is basically 52100 with a tungsten addition, which sounds fantastic but I still haven't tried it myself. That said, it doesn't have especially high abrasion resistance, even at 68 rc or whatever. There's no way it can hold a fine edge anywhere near a "10v class" edge holding steel like say ZDP. According to Larrin it's "edge retention" at 68 rc is about equal to VG10 at 60 rc. He personally rates it at 5.5 for toughness and 4.5 for edge retention. Super blue is rated 2.5 and 3.5. ZDP is rated 2 and 8 and HAP40 is rated 4.5 and 6, tough you should take those ratings with a grain of salt as they are just rough generalizations.
 
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